nsupdate ------RFC 2136 (dynamic DNS updates ) -----> DNS-Server

DNSSEC

# nsupdate
> server ns.mydns.com
> update delete oldhost.example.com. A
> update add newhost.example.com. 86400 A 192.168.254.117
> send
> quit

$ dnssec-keygen -a hmac-md5 -b 128 -n HOST ???

-a   RSAMD5, RSA, DSA, DH 及 HMAC-MD5
-n   HOST | ZONE | USER
-b <n bit>                             # 加密的密碼長度

[2.] 手動讀取 public key檔，更新 ddns
cd /var/named/ddns/

nsupdate -y 'YOUR_KEY_STRING'

nsupdate -k YOUR_KEY_FILE.key -v YOUR_CMD.txt